dangerous modulators ! - UK Vintage Radio Repair and Restoration Discussion Forum

oldeurope · 25th Jun 2005, 11:26 am

Hi,
I found this in the description of the LV20.

http://images.google.de/imgres?imgur...lr%3D%26sa%3DG

" I was half way through the restoration of this set, when I accidentally connected my VHF modulator to the live chassis and blew the modulator up. Doh! "

It is importand to make the areal output of the modulator
potential free and use an isulatet box for it.

This should be standard for a thing used with vintage equipment.
Look in my modulator thrads and the schematic how it can be
made. The caps are so called Y- caps. For your safety use only
this with an Y written on.

Kind regards
Darius

In the pics you can see the potential free coax RF output of
the London Birmingham modulator and the new modulator for the
Mark III standard converter

Nickthedentist · 25th Jun 2005, 12:08 pm

Or I suppose you could use one of those isolated aerial sockets salvaged from a typical 1980s TV which used a live-chassis design.

oldeurope · 25th Jun 2005, 12:41 pm

Hi Nickthedentist,
they are female and you need a male

.

Darius

In the pics you can see how it is made in the
Birmingham modulator. I swaped this one with Mike
for the PYE FV1.

Harry Wergs · 25th Jun 2005, 7:40 pm

I suppose you could always make sure that the chassis is connected to mains neutral, and not mains line !!!
Harry

Danny · 28th Jun 2005, 10:29 pm

hi all i have a distribution system so all my sets are ready to go when i want
to run them ( the ones ive restored that is) and i used old reclaimed isolators from colour sets. i fitted a coax plug and then plugged it into my dist amp.
then plugged the fly leads into them.
yes you should always make shure the mains is connected the right way round!.

25th Jun 2005, 11:26 am	#1
oldeurope Retired Dormant Member Join Date: Dec 2003 Location: Solingen, Germany Posts: 727	dangerous modulators ! Hi, I found this in the description of the LV20. http://images.google.de/imgres?imgur...lr%3D%26sa%3DG " I was half way through the restoration of this set, when I accidentally connected my VHF modulator to the live chassis and blew the modulator up. Doh! " It is importand to make the areal output of the modulator potential free and use an isulatet box for it. This should be standard for a thing used with vintage equipment. Look in my modulator thrads and the schematic how it can be made. The caps are so called Y- caps. For your safety use only this with an Y written on. Kind regards Darius In the pics you can see the potential free coax RF output of the London Birmingham modulator and the new modulator for the Mark III standard converter Attached Thumbnails Last edited by oldeurope; 25th Jun 2005 at 11:39 am.

25th Jun 2005, 12:08 pm	#2
Nickthedentist Dekatron Join Date: Jan 2005 Location: Oxford, UK. Posts: 17,566	Re: dangerous modulators ! Or I suppose you could use one of those isolated aerial sockets salvaged from a typical 1980s TV which used a live-chassis design.

25th Jun 2005, 12:41 pm	#3
oldeurope Retired Dormant Member Join Date: Dec 2003 Location: Solingen, Germany Posts: 727	Re: dangerous modulators ! Hi Nickthedentist, they are female and you need a male. Darius In the pics you can see how it is made in the Birmingham modulator. I swaped this one with Mike for the PYE FV1. Attached Thumbnails

25th Jun 2005, 7:40 pm	#4
Harry Wergs Retired Dormant Member Join Date: May 2005 Location: North Norfolk Posts: 4	Re: dangerous modulators ! I suppose you could always make sure that the chassis is connected to mains neutral, and not mains line !!! Harry

28th Jun 2005, 10:29 pm	#5
Danny Heptode Join Date: Jul 2003 Location: North Walsham, Norfolk, UK. Posts: 516	Re: dangerous modulators ! hi all i have a distribution system so all my sets are ready to go when i want to run them ( the ones ive restored that is) and i used old reclaimed isolators from colour sets. i fitted a coax plug and then plugged it into my dist amp. then plugged the fly leads into them. yes you should always make shure the mains is connected the right way round!.